Re: Variation of Twins Problem

From: Jim Black (ghytrfvbnmju7654_at_mail.com)
Date: 08/26/04 

Date: 26 Aug 2004 14:21:51 -0700

seppala51@sbcglobal.net wrote in message news:<4122c838.266185986@news.houston.sbcglobal.net>...
> On Tue, 17 Aug 2004 19:11:41 -0700, "N:dlzc D:aol T:com \(dlzc\)" <N:
> dlzc1 D:cox T:net@nospam.com> wrote:
>
> >Dear seppala51:
> >
> ><seppala51@sbcglobal.net> wrote in message
> >news:4122b5a7.261432194@news.houston.sbcglobal.net...
> >> If your only source of information is via mail that takes three weeks
> >> to deliver, and you don't know what the other twin actually did (you
> >> don't have the script), and you don't know if he struck a meteor, I do
> >> not believe that you would actually claim that the other twin is three
> >> weeks younger. Or is that what you would assert?
> >
> >If your only source of information is mail, all you can do is look at the
> >postmark.
> If the post mark is three weeks old, would you assert that the other
> twin is three weeks younger? I suspect that you would not.
> > The world of physics is richer than this.
> >
> >David A. Smith
> My question was using your reasoing, if your only source of
> information was 3 week mail, would you assert that the other twin is
> three weeks younger? For reasons unknown, you seem to imply that the
> difference in ages has to do with how fast information can be sent,
> yet when you are presented with a situation in which information can
> only be sent slowly, you don't seem to use the same logic.
> David

If one had a birthday 3 weeks ago, and one received mail from a twin
about his birthday and the twin is the same age as you, and the
postmark shows the letter was sent 3 weeks ago, one would probably
assume that the twin was the same age as you, at least 3 weeks ago.

But here are some questions for you: What if there is no postmark?
What do you do then? How do you know how old your twin is? Assuming
that there is no other source of information about your twin faster
than the mail, even in principle, can you know how old your twin is?
And if the statement that the twins are the same age can never be
tested, does it have any meaning?

Relevant Pages

  • Re: Time.
    ... > Next we speak of the age of a person or body. ... > In other words when I observe my twin brother to be one year younger ... > am because his home planet is one light year away from the earth. ... they are 'believers' or 'nonbelievers' in relativity theory. ...
    (sci.physics.relativity)
  • Re: A Symmetric Twins Conundrum
    ... measurements of Inertial observers) warrants being called a "concept ... If, for example, Mike were to calculate twin B's age at ... values based on the perspective of some observer. ...
    (sci.physics.relativity)
  • Re: Grandfather Clocks and Relativity
    ... Einstein's notions of time and space must apply to all clocks. ... That made no sense to me since a twin cannot reset his age ... twin underwent the acceleration. ...
    (sci.physics.relativity)
  • Re: The David Twin paradox - for STRICH
    ... In system K the twins have the same age 0 at time t = 0. ... At event = twin A suddenly moves with velocity v towards ...     Wordline of origin of K: ... Only analyses is correct as you used a frame K at ...
    (sci.physics.relativity)
  • Re: Twin Fallacy revisited
    ... Using the Lorentz TE for time, the time in B slows by a factor ~gamma. ... B is thus aging slower than A, ... each twin expects the other to have aged less. ... Twin A, age 47, looks at twin B very far away, age 52, and sees that B ...
    (sci.physics)